Multiple-floor furnace for roasting ores.



R. SGHERFENBBRG.

MULTIPLE FLOOR FURNACE FOR ROASTING GEES. APPLICATION FILED NOY. 21, 1911.

Lflmfime Patented Apr. 1, 1913.

3 BHEETS-BHEET 1.

R. SQHERPENBERG. MULTIPLE FLOOR FURNACE FOR ROASTING ORES.

APPLIOATION I'ILED NOV. 21, 1911.

L5K584 Patented'Apr. 1, 1913.

3 BHEETS-8HEET 2.

R. SGHERFENBERG.

MULTIPLE FLOOR FURNACE. FOR ROASTING onns.

APPLICATION FILED NOV. 21, 1911.

3 sums-sum a.

Patented Apr. 1

' uNITE STATES PATENT oFruoE.

nnrnno'tn scnnnrnnsnne, on BERLIN, GEiMANY.

MULTIPLE-FLOQR summon m aoss'rme To all whom it may concern:

Be it known that I, REINHOLD SOI-IERFEN- BERG, of Berlin, Germany, a subject of-the King of Prussia, and whose post-oflice-address is Rosenheimers-trasse 29*, Berlin, Kingdom of Prussia, German Empire, have invented a new and useful Multiple-Floor Furnace for Roasting Ores, of which the "followingds a specification.

In mechanical ore roasting furnaces with several superposed hearths according to Me- Dougalls system (see British Patents Nos.

3985/83 and 22504/91) the iron pyrites to be, roasted is conveyed by means .of a stirring 5 device through all the floors from the top downward and leaves the furnace at the bottom floor in the form of clinkers. The

atmospheric air re uired for burning sulfur is admitted throug air branches into the bottom floor and follows the same path as the ore but in the opposite direction, to the 1 top where it is discharged from the furnace in the form of gas (80,) produced ,by mixing with the sulfur vapors and is conveyed superheated to a temperature of about 200 250 above the burning point of the sulfur in the ore, which, as is well known, amounts to 7 00. Owing to this superheating of the furnace, all the iron parts in the interior of the furnace, are of course quickly destroyed and decom osed into iron sulfid. From the superheate hearths there is further formed the .so-called enamel and the incandescent layers of ore must be raked in these floors by workmen with long iron rakes at regular intervals, and the enamel removed. Moreover, excessive temperature with insufficeint supply of fresh air, brings about a volatilization. and sublimation of sulfur. If

in order to obviate that drawback, it were attempted to keep the temperature in these upper floors of known. furnaces at only 700, the charge of the roasting material as well v v Specification 01. Letters Patent. Application filed November 21, 1911'. Serial No. 661,474.-

furnace would become very For that reason, it has been away for further treatment. This method ORES.

Patented Apr. 1,1913. y,

as the quantityof air, would have tube mnsidemblyc and the out-put or the Pl? to the size.

small compared-1 necessary hitherto to work furnaceswith an, f'

excess of air and with superheated floors,- and apart from the work of raking which is very unhealthy forthe men, the cost of repairs has been very heavy. Moreover," owing to the excessof air sulfuric acid trioxid'SO is formed which has a very dis-.

turbing'eifect on some further treatment,

for instance in the manufacture of sulfites.

The above drawbacks are obviated by the present invention, and the output of the furnacewith a working temperatureof 7 00 can be made nearly four times as great as that of furnaces working with-superheated floors, and at the same time the unhealthy raking work and repairs are done away with.

lFn the furnace according to this invention the. gases enriched with 80,, are conveyed from the single floors direct into the-uppermost floor forming a mixing chamber andfresh air free from S0 is introduced after having been subjected to preliminary heating into the floors directly connected to the said mixing chamber. In that way the temperature of the furnace can be regulated exactly in all the floors, more particularly in the centraland upper ones, so that the injurious superheating in the upper floors, and its consequences, are avoided, and v at the same time a quantity of air corresponding to the progressing roasting process, and

much greater in proportion is supplied to the central and upper floors.

Various apparatus can be used for carrying out the process, for instance the conduit for forcing the fresh air into all the floors, or only into the central and upper floors,

as well as the conduits for conveying the gases directly intothe uppermost floor, can be placed in the wall of the furnace. The

' preliminary heating in that case would be however insufficient, unless in special cases in which air already heated is available. Consequently, it is advantageous to use an apparatus in which the heated fresh air is taken from the air whichis forced into the stirring device spindle and cools the stirring device.

Two preferred constructions of an ore roasting furnace are shown in the accompanying drawing, Figure 1 showing one conis a cross-section on the line J-K of the struction in longitudinal section and Figs. 2-4 cross-sections on lines C D, E F, and H respectively of this construction. Fig. 5 is' a longitudinal section and Fig. 6

second construction.

The furnace shown in Figs. 1 and 2, contains in, the known manner a number of hearths a a (1 arranged one above another like floors, within'acasing h. The

second, fourth and sixth hearths are provided in the known manner with a central passage opening 2' for the ore while the first, third and fifth hearths are provided with an ore passage opening j, (Fig. 2) arranged at the circumference. Above .each hearth rotates a stirring arm or arms is, the blades of the said arms being arranged in the known manner alternately 1n oppositedirections, in accordance with the direction of movement of the roasted material changing from insideto outward and from outside to inward in the superposed floors. The ore is admitted from the top through the charging branch or hopper b and is discharged from the bottom floor of the furnace in the form of clinkers through an outlet channel 0. The stirring arms is are mounted on a double walled spindle slowly driven by an outer gear (not shown), the said spindle consisting of an innertube m closed at the top, and of an outer jacket tube a closed at the bottom. The stirring arms]: start from the inner tube m and are provided in the known manner with intermediate walls 0 for guiding the air forced from below into the inner tube m by means of a pump, fan, blower or the like (not shown) located at any suitable place outsid the furnace. In the upper floors above the hearths a a a a1 a and a the outer tube 11 is provided with openings 1' for the escape of the air, regulated, by means ofslides or the like. According to this invention there are provided a number of wall conduits 19-25 starting from the floors above the hearths (L -a, respectively, and leading direct to the uppermost floor used as a mixing chamber, above the hearth a. The gases enriched with S0 and mixed above the hearth a by the stirring device, are drawn off through the branch (1. After the furnace is started, the heated fresh air forced into the floors from the stirring apparatus, is adjusted by means of the slides at the openings 1' so that the temperature in the upper floors does not reach the injurious limit. After this regulation has been'once effected, the furnace can be worked permanently without any further adjustment of .the corresponding slides, and has then the advantages mentioned in the introduction. The enriched gases from all the floors are conveyed direct into the uppermost floor above the hearth a", by arranging four conduits t (Fig. 1-) distributed about the circumference and starting from the lowest floor, above the hearth a From the next higher floor, above the hearth a start also four conduits t distributed on the circumference and leading intothe uppermost mixing chamber. F rom the next higher floor a", eight conduits t distributed on the circumference, pass into the uppermost mixing chamber, and in a similar manner from each of the next floors, above the hearths a a a, eight such conduits t t and t, so that all these conduits distributed on the circumference of the single floors, open into the uppermost mixing chamber, above the hearth a, as shown in Fig. 2.

In the modified construction of the furnaee shown in Figs. 5 and 6 the enriched gases are conveyed from allthe floors direct into the uppermost floor or mixing chamber in the same manner as described and shown for the furnace of Figs. 14. The heated fresh air, taken from the hollow spindle of the stirring apparatus, passes into a conduit or tube w and then through tubes m extending from the tube w into annular chambers y provided with circumferential openings y. In the tubes as are inserted outside of the furnace regulating slides or clapets z. This modification involves the advantagetha-t the air-distribution can be regulated from outside and without stoppingthe stirring apparatus.

That I do claim as my invention, and desire to secure by Letters Patent of the United States, is

1. In a multiple floor ore roasting furnacethe combination of a plurality of floors, passages arranged in the floors alternately centrally and circumferentially, stirring arms mounted on a hollow rotating spindle with means for forcing air free from SO into the floors and means for conveying the gases enriched with SO from floors directly into the uppermost floor, substantially as set forth.

2. In a multiple floor ore roasting furnace the combination of a plurality of floors, ,passages arranged in the floors alternately centrally and circumferentially, stirring arms mounted on a hollow rotating spindle with means for forcing air free from SO through the hollow rotating spindle'into the individual floors and means for conveying the gases enriched with SO from floors directly into the uppermost floor, substantially as set forth.

3. In a multiple floor ore roasting furnace the combination of a plurality of floors,

passages arranged in the floors alternately omg'se floors directly into the uppermost floor and air, substantially as set forth-.- 4 4. In a multlple floor ore roasting furnace the combination of a plurality of floors, passages arranged in the floors alternately centrally and circumferentially, stirring arms mounted on a hollow rotating spindle with means for forcing air free from S0; into the floors, separate conduits distributed" on the circumference of the single floors for: conveying the gases enriched with S0 directly into the uppermost floor and means for regulating the passage of the said air,

substantially as set'forth. a

5. "In a multiple floor oreroasting furnace the combination of a plurality of floors,

passages arranged in the floors alternately a plurality of tubes connected with stirring spindle, theouter jacket tube of the hollow rotating spindle for conveying air free from SO into the centrally and circumferentially, arms mounted on-a hollow rotating floors, separate conduits distributed on the circumference ofthe single 'floorsfor conveying the gases enriched with SO directly into the uppermost floor'andmeans for regulating the passage of'th id air, substan- ,tiallyas set forth; c' i In'testimony' whereof-I have-hereunto set my-hand in presence of two subscribing wit- DBSSGS.

v REINHOLD-SOHERFENBERG. Witneseszy Y HENRY iliSPER,

WOLDEMAR HAUPT. 

